mbed-os 6.10 versione
cmsis_dsp/TransformFunctions/arm_cfft_radix4_q15.c@2:da51fb522205, 2013-05-30 (annotated)
- Committer:
- emilmont
- Date:
- Thu May 30 17:10:11 2013 +0100
- Revision:
- 2:da51fb522205
- Parent:
- 1:fdd22bb7aa52
- Child:
- 3:7a284390b0ce
Keep "cmsis-dsp" module in synch with its source
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
emilmont | 1:fdd22bb7aa52 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
emilmont | 1:fdd22bb7aa52 | 4 | * $Date: 15. February 2012 |
emilmont | 2:da51fb522205 | 5 | * $Revision: V1.1.0 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 2:da51fb522205 | 7 | * Project: CMSIS DSP Library |
emilmont | 2:da51fb522205 | 8 | * Title: arm_cfft_radix4_q15.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 2:da51fb522205 | 10 | * Description: This file has function definition of Radix-4 FFT & IFFT function and |
emilmont | 2:da51fb522205 | 11 | * In-place bit reversal using bit reversal table |
emilmont | 1:fdd22bb7aa52 | 12 | * |
emilmont | 1:fdd22bb7aa52 | 13 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 14 | * |
emilmont | 1:fdd22bb7aa52 | 15 | * Version 1.1.0 2012/02/15 |
emilmont | 1:fdd22bb7aa52 | 16 | * Updated with more optimizations, bug fixes and minor API changes. |
emilmont | 1:fdd22bb7aa52 | 17 | * |
emilmont | 1:fdd22bb7aa52 | 18 | * Version 1.0.10 2011/7/15 |
emilmont | 1:fdd22bb7aa52 | 19 | * Big Endian support added and Merged M0 and M3/M4 Source code. |
emilmont | 1:fdd22bb7aa52 | 20 | * |
emilmont | 1:fdd22bb7aa52 | 21 | * Version 1.0.3 2010/11/29 |
emilmont | 1:fdd22bb7aa52 | 22 | * Re-organized the CMSIS folders and updated documentation. |
emilmont | 1:fdd22bb7aa52 | 23 | * |
emilmont | 1:fdd22bb7aa52 | 24 | * Version 1.0.2 2010/11/11 |
emilmont | 1:fdd22bb7aa52 | 25 | * Documentation updated. |
emilmont | 1:fdd22bb7aa52 | 26 | * |
emilmont | 1:fdd22bb7aa52 | 27 | * Version 1.0.1 2010/10/05 |
emilmont | 1:fdd22bb7aa52 | 28 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 29 | * |
emilmont | 1:fdd22bb7aa52 | 30 | * Version 1.0.0 2010/09/20 |
emilmont | 1:fdd22bb7aa52 | 31 | * Production release and review comments incorporated. |
emilmont | 1:fdd22bb7aa52 | 32 | * |
emilmont | 1:fdd22bb7aa52 | 33 | * Version 0.0.5 2010/04/26 |
emilmont | 2:da51fb522205 | 34 | * incorporated review comments and updated with latest CMSIS layer |
emilmont | 1:fdd22bb7aa52 | 35 | * |
emilmont | 1:fdd22bb7aa52 | 36 | * Version 0.0.3 2010/03/10 |
emilmont | 1:fdd22bb7aa52 | 37 | * Initial version |
emilmont | 1:fdd22bb7aa52 | 38 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 39 | |
emilmont | 1:fdd22bb7aa52 | 40 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 41 | |
emilmont | 1:fdd22bb7aa52 | 42 | /** |
emilmont | 1:fdd22bb7aa52 | 43 | * @ingroup groupTransforms |
emilmont | 1:fdd22bb7aa52 | 44 | */ |
emilmont | 1:fdd22bb7aa52 | 45 | |
emilmont | 1:fdd22bb7aa52 | 46 | /** |
emilmont | 1:fdd22bb7aa52 | 47 | * @addtogroup Radix4_CFFT_CIFFT |
emilmont | 1:fdd22bb7aa52 | 48 | * @{ |
emilmont | 1:fdd22bb7aa52 | 49 | */ |
emilmont | 1:fdd22bb7aa52 | 50 | |
emilmont | 1:fdd22bb7aa52 | 51 | |
emilmont | 1:fdd22bb7aa52 | 52 | /** |
emilmont | 1:fdd22bb7aa52 | 53 | * @details |
emilmont | 1:fdd22bb7aa52 | 54 | * @brief Processing function for the Q15 CFFT/CIFFT. |
emilmont | 1:fdd22bb7aa52 | 55 | * @param[in] *S points to an instance of the Q15 CFFT/CIFFT structure. |
emilmont | 1:fdd22bb7aa52 | 56 | * @param[in, out] *pSrc points to the complex data buffer. Processing occurs in-place. |
emilmont | 1:fdd22bb7aa52 | 57 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 58 | * |
emilmont | 1:fdd22bb7aa52 | 59 | * \par Input and output formats: |
emilmont | 1:fdd22bb7aa52 | 60 | * \par |
emilmont | 1:fdd22bb7aa52 | 61 | * Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. |
emilmont | 1:fdd22bb7aa52 | 62 | * Hence the output format is different for different FFT sizes. |
emilmont | 1:fdd22bb7aa52 | 63 | * The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT: |
emilmont | 1:fdd22bb7aa52 | 64 | * \par |
emilmont | 1:fdd22bb7aa52 | 65 | * \image html CFFTQ15.gif "Input and Output Formats for Q15 CFFT" |
emilmont | 1:fdd22bb7aa52 | 66 | * \image html CIFFTQ15.gif "Input and Output Formats for Q15 CIFFT" |
emilmont | 1:fdd22bb7aa52 | 67 | */ |
emilmont | 1:fdd22bb7aa52 | 68 | |
emilmont | 1:fdd22bb7aa52 | 69 | void arm_cfft_radix4_q15( |
emilmont | 1:fdd22bb7aa52 | 70 | const arm_cfft_radix4_instance_q15 * S, |
emilmont | 1:fdd22bb7aa52 | 71 | q15_t * pSrc) |
emilmont | 1:fdd22bb7aa52 | 72 | { |
emilmont | 1:fdd22bb7aa52 | 73 | if(S->ifftFlag == 1u) |
emilmont | 1:fdd22bb7aa52 | 74 | { |
emilmont | 1:fdd22bb7aa52 | 75 | /* Complex IFFT radix-4 */ |
emilmont | 1:fdd22bb7aa52 | 76 | arm_radix4_butterfly_inverse_q15(pSrc, S->fftLen, S->pTwiddle, |
emilmont | 1:fdd22bb7aa52 | 77 | S->twidCoefModifier); |
emilmont | 1:fdd22bb7aa52 | 78 | } |
emilmont | 1:fdd22bb7aa52 | 79 | else |
emilmont | 1:fdd22bb7aa52 | 80 | { |
emilmont | 1:fdd22bb7aa52 | 81 | /* Complex FFT radix-4 */ |
emilmont | 1:fdd22bb7aa52 | 82 | arm_radix4_butterfly_q15(pSrc, S->fftLen, S->pTwiddle, |
emilmont | 1:fdd22bb7aa52 | 83 | S->twidCoefModifier); |
emilmont | 1:fdd22bb7aa52 | 84 | } |
emilmont | 1:fdd22bb7aa52 | 85 | |
emilmont | 1:fdd22bb7aa52 | 86 | if(S->bitReverseFlag == 1u) |
emilmont | 1:fdd22bb7aa52 | 87 | { |
emilmont | 1:fdd22bb7aa52 | 88 | /* Bit Reversal */ |
emilmont | 1:fdd22bb7aa52 | 89 | arm_bitreversal_q15(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable); |
emilmont | 1:fdd22bb7aa52 | 90 | } |
emilmont | 1:fdd22bb7aa52 | 91 | |
emilmont | 1:fdd22bb7aa52 | 92 | } |
emilmont | 1:fdd22bb7aa52 | 93 | |
emilmont | 1:fdd22bb7aa52 | 94 | /** |
emilmont | 1:fdd22bb7aa52 | 95 | * @} end of Radix4_CFFT_CIFFT group |
emilmont | 1:fdd22bb7aa52 | 96 | */ |
emilmont | 1:fdd22bb7aa52 | 97 | |
emilmont | 1:fdd22bb7aa52 | 98 | /* |
emilmont | 1:fdd22bb7aa52 | 99 | * Radix-4 FFT algorithm used is : |
emilmont | 1:fdd22bb7aa52 | 100 | * |
emilmont | 1:fdd22bb7aa52 | 101 | * Input real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 102 | * x(n) = xa + j * ya |
emilmont | 1:fdd22bb7aa52 | 103 | * x(n+N/4 ) = xb + j * yb |
emilmont | 1:fdd22bb7aa52 | 104 | * x(n+N/2 ) = xc + j * yc |
emilmont | 1:fdd22bb7aa52 | 105 | * x(n+3N 4) = xd + j * yd |
emilmont | 1:fdd22bb7aa52 | 106 | * |
emilmont | 1:fdd22bb7aa52 | 107 | * |
emilmont | 1:fdd22bb7aa52 | 108 | * Output real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 109 | * x(4r) = xa'+ j * ya' |
emilmont | 1:fdd22bb7aa52 | 110 | * x(4r+1) = xb'+ j * yb' |
emilmont | 1:fdd22bb7aa52 | 111 | * x(4r+2) = xc'+ j * yc' |
emilmont | 1:fdd22bb7aa52 | 112 | * x(4r+3) = xd'+ j * yd' |
emilmont | 1:fdd22bb7aa52 | 113 | * |
emilmont | 1:fdd22bb7aa52 | 114 | * |
emilmont | 1:fdd22bb7aa52 | 115 | * Twiddle factors for radix-4 FFT: |
emilmont | 1:fdd22bb7aa52 | 116 | * Wn = co1 + j * (- si1) |
emilmont | 1:fdd22bb7aa52 | 117 | * W2n = co2 + j * (- si2) |
emilmont | 1:fdd22bb7aa52 | 118 | * W3n = co3 + j * (- si3) |
emilmont | 1:fdd22bb7aa52 | 119 | |
emilmont | 1:fdd22bb7aa52 | 120 | * The real and imaginary output values for the radix-4 butterfly are |
emilmont | 1:fdd22bb7aa52 | 121 | * xa' = xa + xb + xc + xd |
emilmont | 1:fdd22bb7aa52 | 122 | * ya' = ya + yb + yc + yd |
emilmont | 1:fdd22bb7aa52 | 123 | * xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 124 | * yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 125 | * xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 126 | * yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 127 | * xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 128 | * yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 129 | * |
emilmont | 1:fdd22bb7aa52 | 130 | */ |
emilmont | 1:fdd22bb7aa52 | 131 | |
emilmont | 1:fdd22bb7aa52 | 132 | /** |
emilmont | 1:fdd22bb7aa52 | 133 | * @brief Core function for the Q15 CFFT butterfly process. |
emilmont | 1:fdd22bb7aa52 | 134 | * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type. |
emilmont | 1:fdd22bb7aa52 | 135 | * @param[in] fftLen length of the FFT. |
emilmont | 1:fdd22bb7aa52 | 136 | * @param[in] *pCoef16 points to twiddle coefficient buffer. |
emilmont | 1:fdd22bb7aa52 | 137 | * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. |
emilmont | 1:fdd22bb7aa52 | 138 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 139 | */ |
emilmont | 1:fdd22bb7aa52 | 140 | |
emilmont | 1:fdd22bb7aa52 | 141 | void arm_radix4_butterfly_q15( |
emilmont | 1:fdd22bb7aa52 | 142 | q15_t * pSrc16, |
emilmont | 1:fdd22bb7aa52 | 143 | uint32_t fftLen, |
emilmont | 1:fdd22bb7aa52 | 144 | q15_t * pCoef16, |
emilmont | 1:fdd22bb7aa52 | 145 | uint32_t twidCoefModifier) |
emilmont | 1:fdd22bb7aa52 | 146 | { |
emilmont | 1:fdd22bb7aa52 | 147 | |
emilmont | 1:fdd22bb7aa52 | 148 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 149 | |
emilmont | 1:fdd22bb7aa52 | 150 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 151 | |
emilmont | 1:fdd22bb7aa52 | 152 | q31_t R, S, T, U; |
emilmont | 1:fdd22bb7aa52 | 153 | q31_t C1, C2, C3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 154 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 155 | q15_t in; |
emilmont | 1:fdd22bb7aa52 | 156 | |
emilmont | 1:fdd22bb7aa52 | 157 | q15_t *ptr1; |
emilmont | 1:fdd22bb7aa52 | 158 | |
emilmont | 1:fdd22bb7aa52 | 159 | |
emilmont | 1:fdd22bb7aa52 | 160 | |
emilmont | 1:fdd22bb7aa52 | 161 | q31_t xaya, xbyb, xcyc, xdyd; |
emilmont | 1:fdd22bb7aa52 | 162 | |
emilmont | 1:fdd22bb7aa52 | 163 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 164 | |
emilmont | 1:fdd22bb7aa52 | 165 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 166 | |
emilmont | 1:fdd22bb7aa52 | 167 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 168 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 169 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 170 | |
emilmont | 1:fdd22bb7aa52 | 171 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 172 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 173 | |
emilmont | 1:fdd22bb7aa52 | 174 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 175 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 176 | |
emilmont | 1:fdd22bb7aa52 | 177 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 178 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 179 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 180 | |
emilmont | 1:fdd22bb7aa52 | 181 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 182 | |
emilmont | 1:fdd22bb7aa52 | 183 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 184 | do |
emilmont | 1:fdd22bb7aa52 | 185 | { |
emilmont | 1:fdd22bb7aa52 | 186 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 187 | |
emilmont | 1:fdd22bb7aa52 | 188 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 189 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 190 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 191 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 192 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 193 | |
emilmont | 1:fdd22bb7aa52 | 194 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 195 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 196 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 197 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 198 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 199 | |
emilmont | 1:fdd22bb7aa52 | 200 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 201 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 202 | in = ((int16_t) (S & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 203 | S = ((S >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 204 | |
emilmont | 1:fdd22bb7aa52 | 205 | /* R = packed((ya + yc), (xa + xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 206 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 207 | |
emilmont | 1:fdd22bb7aa52 | 208 | /* S = packed((ya - yc), (xa - xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 209 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 210 | |
emilmont | 1:fdd22bb7aa52 | 211 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 212 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 213 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 214 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 215 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 216 | |
emilmont | 1:fdd22bb7aa52 | 217 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 218 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 219 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 220 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 221 | |
emilmont | 1:fdd22bb7aa52 | 222 | /* T = packed((yb + yd), (xb + xd) ) */ |
emilmont | 1:fdd22bb7aa52 | 223 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 224 | |
emilmont | 1:fdd22bb7aa52 | 225 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 226 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 227 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 228 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 229 | |
emilmont | 1:fdd22bb7aa52 | 230 | /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 231 | R = __QSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 232 | |
emilmont | 1:fdd22bb7aa52 | 233 | /* co2 & si2 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 234 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 235 | |
emilmont | 1:fdd22bb7aa52 | 236 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 237 | |
emilmont | 1:fdd22bb7aa52 | 238 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 239 | out1 = __SMUAD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 240 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 241 | out2 = __SMUSDX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 242 | |
emilmont | 1:fdd22bb7aa52 | 243 | #else |
emilmont | 1:fdd22bb7aa52 | 244 | |
emilmont | 1:fdd22bb7aa52 | 245 | /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 246 | out1 = __SMUSDX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 247 | /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 248 | out2 = __SMUAD(C2, R); |
emilmont | 1:fdd22bb7aa52 | 249 | |
emilmont | 1:fdd22bb7aa52 | 250 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 251 | |
emilmont | 1:fdd22bb7aa52 | 252 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 253 | /* T = packed(yb, xb) */ |
emilmont | 1:fdd22bb7aa52 | 254 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 255 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 256 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 257 | |
emilmont | 1:fdd22bb7aa52 | 258 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 259 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 260 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 261 | (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 262 | |
emilmont | 1:fdd22bb7aa52 | 263 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 264 | /* U = packed(yd, xd) */ |
emilmont | 1:fdd22bb7aa52 | 265 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 266 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 267 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 268 | |
emilmont | 1:fdd22bb7aa52 | 269 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 270 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 271 | |
emilmont | 1:fdd22bb7aa52 | 272 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 273 | |
emilmont | 1:fdd22bb7aa52 | 274 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 275 | R = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 276 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 277 | S = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 278 | |
emilmont | 1:fdd22bb7aa52 | 279 | #else |
emilmont | 1:fdd22bb7aa52 | 280 | |
emilmont | 1:fdd22bb7aa52 | 281 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 282 | R = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 283 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 284 | S = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 285 | |
emilmont | 1:fdd22bb7aa52 | 286 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 287 | |
emilmont | 1:fdd22bb7aa52 | 288 | /* co1 & si1 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 289 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 290 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 291 | |
emilmont | 1:fdd22bb7aa52 | 292 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 293 | |
emilmont | 1:fdd22bb7aa52 | 294 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 295 | out1 = __SMUAD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 296 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 297 | out2 = __SMUSDX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 298 | |
emilmont | 1:fdd22bb7aa52 | 299 | #else |
emilmont | 1:fdd22bb7aa52 | 300 | |
emilmont | 1:fdd22bb7aa52 | 301 | /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 302 | out1 = __SMUSDX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 303 | /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 304 | out2 = __SMUAD(C1, S); |
emilmont | 1:fdd22bb7aa52 | 305 | |
emilmont | 1:fdd22bb7aa52 | 306 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 307 | |
emilmont | 1:fdd22bb7aa52 | 308 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 309 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 310 | ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 311 | |
emilmont | 1:fdd22bb7aa52 | 312 | |
emilmont | 1:fdd22bb7aa52 | 313 | /* co3 & si3 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 314 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 315 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 316 | |
emilmont | 1:fdd22bb7aa52 | 317 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 318 | |
emilmont | 1:fdd22bb7aa52 | 319 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 320 | out1 = __SMUAD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 321 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 322 | out2 = __SMUSDX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 323 | |
emilmont | 1:fdd22bb7aa52 | 324 | #else |
emilmont | 1:fdd22bb7aa52 | 325 | |
emilmont | 1:fdd22bb7aa52 | 326 | /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 327 | out1 = __SMUSDX(R, C3) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 328 | /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 329 | out2 = __SMUAD(C3, R); |
emilmont | 1:fdd22bb7aa52 | 330 | |
emilmont | 1:fdd22bb7aa52 | 331 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 332 | |
emilmont | 1:fdd22bb7aa52 | 333 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 334 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 335 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 336 | |
emilmont | 1:fdd22bb7aa52 | 337 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 338 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 339 | |
emilmont | 1:fdd22bb7aa52 | 340 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 341 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 342 | |
emilmont | 1:fdd22bb7aa52 | 343 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 344 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 345 | |
emilmont | 1:fdd22bb7aa52 | 346 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 347 | |
emilmont | 1:fdd22bb7aa52 | 348 | |
emilmont | 1:fdd22bb7aa52 | 349 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 350 | |
emilmont | 1:fdd22bb7aa52 | 351 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 352 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 353 | |
emilmont | 1:fdd22bb7aa52 | 354 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 355 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 356 | { |
emilmont | 1:fdd22bb7aa52 | 357 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 358 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 359 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 360 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 361 | |
emilmont | 1:fdd22bb7aa52 | 362 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 363 | { |
emilmont | 1:fdd22bb7aa52 | 364 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 365 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 366 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 367 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 368 | |
emilmont | 1:fdd22bb7aa52 | 369 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 370 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 371 | |
emilmont | 1:fdd22bb7aa52 | 372 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 373 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 374 | { |
emilmont | 1:fdd22bb7aa52 | 375 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 376 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 377 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 378 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 379 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 380 | |
emilmont | 1:fdd22bb7aa52 | 381 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 382 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 383 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 384 | |
emilmont | 1:fdd22bb7aa52 | 385 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 386 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 387 | |
emilmont | 1:fdd22bb7aa52 | 388 | /* R = packed( (ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 389 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 390 | |
emilmont | 1:fdd22bb7aa52 | 391 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 392 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 393 | |
emilmont | 1:fdd22bb7aa52 | 394 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 395 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 396 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 397 | |
emilmont | 1:fdd22bb7aa52 | 398 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 399 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 400 | |
emilmont | 1:fdd22bb7aa52 | 401 | /* T = packed( (yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 402 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 403 | |
emilmont | 1:fdd22bb7aa52 | 404 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 405 | |
emilmont | 1:fdd22bb7aa52 | 406 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 407 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 408 | out1 = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 409 | in = ((int16_t) (out1 & 0xFFFF)) >> 1; |
emilmont | 1:fdd22bb7aa52 | 410 | out1 = ((out1 >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 411 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = out1; |
emilmont | 1:fdd22bb7aa52 | 412 | |
emilmont | 1:fdd22bb7aa52 | 413 | /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 414 | R = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 415 | |
emilmont | 1:fdd22bb7aa52 | 416 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 417 | |
emilmont | 1:fdd22bb7aa52 | 418 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 419 | out1 = __SMUAD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 420 | |
emilmont | 1:fdd22bb7aa52 | 421 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 422 | out2 = __SMUSDX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 423 | |
emilmont | 1:fdd22bb7aa52 | 424 | #else |
emilmont | 1:fdd22bb7aa52 | 425 | |
emilmont | 1:fdd22bb7aa52 | 426 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 427 | out1 = __SMUSDX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 428 | |
emilmont | 1:fdd22bb7aa52 | 429 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 430 | out2 = __SMUAD(C2, R); |
emilmont | 1:fdd22bb7aa52 | 431 | |
emilmont | 1:fdd22bb7aa52 | 432 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 433 | |
emilmont | 1:fdd22bb7aa52 | 434 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 435 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 436 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 437 | |
emilmont | 1:fdd22bb7aa52 | 438 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 439 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 440 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 441 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 442 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 443 | |
emilmont | 1:fdd22bb7aa52 | 444 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 445 | |
emilmont | 1:fdd22bb7aa52 | 446 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 447 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 448 | |
emilmont | 1:fdd22bb7aa52 | 449 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 450 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 451 | |
emilmont | 1:fdd22bb7aa52 | 452 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 453 | |
emilmont | 1:fdd22bb7aa52 | 454 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 455 | R = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 456 | |
emilmont | 1:fdd22bb7aa52 | 457 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 458 | S = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 459 | |
emilmont | 1:fdd22bb7aa52 | 460 | |
emilmont | 1:fdd22bb7aa52 | 461 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 462 | out1 = __SMUAD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 463 | out2 = __SMUSDX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 464 | |
emilmont | 1:fdd22bb7aa52 | 465 | #else |
emilmont | 1:fdd22bb7aa52 | 466 | |
emilmont | 1:fdd22bb7aa52 | 467 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 468 | R = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 469 | |
emilmont | 1:fdd22bb7aa52 | 470 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 471 | S = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 472 | |
emilmont | 1:fdd22bb7aa52 | 473 | |
emilmont | 1:fdd22bb7aa52 | 474 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 475 | out1 = __SMUSDX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 476 | out2 = __SMUAD(C1, S); |
emilmont | 1:fdd22bb7aa52 | 477 | |
emilmont | 1:fdd22bb7aa52 | 478 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 479 | |
emilmont | 1:fdd22bb7aa52 | 480 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 481 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 482 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 483 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 484 | |
emilmont | 1:fdd22bb7aa52 | 485 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 486 | |
emilmont | 1:fdd22bb7aa52 | 487 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 488 | |
emilmont | 1:fdd22bb7aa52 | 489 | out1 = __SMUAD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 490 | out2 = __SMUSDX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 491 | |
emilmont | 1:fdd22bb7aa52 | 492 | #else |
emilmont | 1:fdd22bb7aa52 | 493 | |
emilmont | 1:fdd22bb7aa52 | 494 | out1 = __SMUSDX(R, C3) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 495 | out2 = __SMUAD(C3, R); |
emilmont | 1:fdd22bb7aa52 | 496 | |
emilmont | 1:fdd22bb7aa52 | 497 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 498 | |
emilmont | 1:fdd22bb7aa52 | 499 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 500 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 501 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 502 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 503 | } |
emilmont | 1:fdd22bb7aa52 | 504 | } |
emilmont | 1:fdd22bb7aa52 | 505 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 506 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 507 | } |
emilmont | 1:fdd22bb7aa52 | 508 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 509 | |
emilmont | 1:fdd22bb7aa52 | 510 | |
emilmont | 1:fdd22bb7aa52 | 511 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 512 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 513 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 514 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 515 | |
emilmont | 1:fdd22bb7aa52 | 516 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 517 | j = fftLen >> 2; |
emilmont | 1:fdd22bb7aa52 | 518 | |
emilmont | 1:fdd22bb7aa52 | 519 | ptr1 = &pSrc16[0]; |
emilmont | 1:fdd22bb7aa52 | 520 | |
emilmont | 1:fdd22bb7aa52 | 521 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 522 | |
emilmont | 1:fdd22bb7aa52 | 523 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 524 | do |
emilmont | 1:fdd22bb7aa52 | 525 | { |
emilmont | 1:fdd22bb7aa52 | 526 | /* Read xa (real), ya(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 527 | xaya = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 528 | |
emilmont | 1:fdd22bb7aa52 | 529 | /* Read xb (real), yb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 530 | xbyb = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 531 | |
emilmont | 1:fdd22bb7aa52 | 532 | /* Read xc (real), yc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 533 | xcyc = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 534 | |
emilmont | 1:fdd22bb7aa52 | 535 | /* Read xd (real), yd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 536 | xdyd = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 537 | |
emilmont | 1:fdd22bb7aa52 | 538 | /* R = packed((ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 539 | R = __QADD16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 540 | |
emilmont | 1:fdd22bb7aa52 | 541 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 542 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 543 | |
emilmont | 1:fdd22bb7aa52 | 544 | /* pointer updation for writing */ |
emilmont | 1:fdd22bb7aa52 | 545 | ptr1 = ptr1 - 8u; |
emilmont | 1:fdd22bb7aa52 | 546 | |
emilmont | 1:fdd22bb7aa52 | 547 | |
emilmont | 1:fdd22bb7aa52 | 548 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 549 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 550 | *__SIMD32(ptr1)++ = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 551 | |
emilmont | 1:fdd22bb7aa52 | 552 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 553 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 554 | |
emilmont | 1:fdd22bb7aa52 | 555 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 556 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 557 | *__SIMD32(ptr1)++ = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 558 | |
emilmont | 1:fdd22bb7aa52 | 559 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 560 | S = __QSUB16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 561 | |
emilmont | 1:fdd22bb7aa52 | 562 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 563 | /* T = packed( (yb - yd), (xb - xd)) */ |
emilmont | 1:fdd22bb7aa52 | 564 | U = __QSUB16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 565 | |
emilmont | 1:fdd22bb7aa52 | 566 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 567 | |
emilmont | 1:fdd22bb7aa52 | 568 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 569 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 570 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 571 | |
emilmont | 1:fdd22bb7aa52 | 572 | |
emilmont | 1:fdd22bb7aa52 | 573 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 574 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 575 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 576 | |
emilmont | 1:fdd22bb7aa52 | 577 | #else |
emilmont | 1:fdd22bb7aa52 | 578 | |
emilmont | 1:fdd22bb7aa52 | 579 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 580 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 581 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 582 | |
emilmont | 1:fdd22bb7aa52 | 583 | |
emilmont | 1:fdd22bb7aa52 | 584 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 585 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 586 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 587 | |
emilmont | 1:fdd22bb7aa52 | 588 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 589 | |
emilmont | 1:fdd22bb7aa52 | 590 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 591 | |
emilmont | 1:fdd22bb7aa52 | 592 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 593 | |
emilmont | 1:fdd22bb7aa52 | 594 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 595 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 596 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 597 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 598 | |
emilmont | 1:fdd22bb7aa52 | 599 | |
emilmont | 1:fdd22bb7aa52 | 600 | #else |
emilmont | 1:fdd22bb7aa52 | 601 | |
emilmont | 1:fdd22bb7aa52 | 602 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 603 | |
emilmont | 1:fdd22bb7aa52 | 604 | q15_t R0, R1, S0, S1, T0, T1, U0, U1; |
emilmont | 1:fdd22bb7aa52 | 605 | q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 606 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 607 | |
emilmont | 1:fdd22bb7aa52 | 608 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 609 | |
emilmont | 1:fdd22bb7aa52 | 610 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 611 | |
emilmont | 1:fdd22bb7aa52 | 612 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 613 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 614 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 615 | |
emilmont | 1:fdd22bb7aa52 | 616 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 617 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 618 | |
emilmont | 1:fdd22bb7aa52 | 619 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 620 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 621 | |
emilmont | 1:fdd22bb7aa52 | 622 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 623 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 624 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 625 | |
emilmont | 1:fdd22bb7aa52 | 626 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 627 | |
emilmont | 1:fdd22bb7aa52 | 628 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 629 | do |
emilmont | 1:fdd22bb7aa52 | 630 | { |
emilmont | 1:fdd22bb7aa52 | 631 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 632 | |
emilmont | 1:fdd22bb7aa52 | 633 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 634 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 635 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 636 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 637 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 638 | |
emilmont | 1:fdd22bb7aa52 | 639 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 640 | |
emilmont | 1:fdd22bb7aa52 | 641 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 642 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 643 | T0 = pSrc16[i0 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 644 | T1 = pSrc16[(i0 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 645 | |
emilmont | 1:fdd22bb7aa52 | 646 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 647 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 648 | S0 = pSrc16[i2 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 649 | S1 = pSrc16[(i2 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 650 | |
emilmont | 1:fdd22bb7aa52 | 651 | /* R0 = (ya + yc) */ |
emilmont | 1:fdd22bb7aa52 | 652 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 653 | /* R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 654 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 655 | |
emilmont | 1:fdd22bb7aa52 | 656 | /* S0 = (ya - yc) */ |
emilmont | 1:fdd22bb7aa52 | 657 | S0 = __SSAT(T0 - S0, 16); |
emilmont | 1:fdd22bb7aa52 | 658 | /* S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 659 | S1 = __SSAT(T1 - S1, 16); |
emilmont | 1:fdd22bb7aa52 | 660 | |
emilmont | 1:fdd22bb7aa52 | 661 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 662 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 663 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 664 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 665 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 666 | |
emilmont | 1:fdd22bb7aa52 | 667 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 668 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 669 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 670 | U1 = pSrc16[(i3 * 2u) + 1] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 671 | |
emilmont | 1:fdd22bb7aa52 | 672 | /* T0 = (yb + yd) */ |
emilmont | 1:fdd22bb7aa52 | 673 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 674 | /* T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 675 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 676 | |
emilmont | 1:fdd22bb7aa52 | 677 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 678 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 679 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 680 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 681 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 682 | |
emilmont | 1:fdd22bb7aa52 | 683 | /* R0 = (ya + yc) - (yb + yd) */ |
emilmont | 1:fdd22bb7aa52 | 684 | /* R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 685 | R0 = __SSAT(R0 - T0, 16u); |
emilmont | 1:fdd22bb7aa52 | 686 | R1 = __SSAT(R1 - T1, 16u); |
emilmont | 1:fdd22bb7aa52 | 687 | |
emilmont | 1:fdd22bb7aa52 | 688 | /* co2 & si2 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 689 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 690 | Si2 = pCoef16[(2u * ic * 2u) + 1]; |
emilmont | 1:fdd22bb7aa52 | 691 | |
emilmont | 1:fdd22bb7aa52 | 692 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 693 | out1 = (short) ((Co2 * R0 + Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 694 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 695 | out2 = (short) ((-Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 696 | |
emilmont | 1:fdd22bb7aa52 | 697 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 698 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 699 | /* T0 = yb, T1 = xb */ |
emilmont | 1:fdd22bb7aa52 | 700 | T0 = pSrc16[i1 * 2u] >> 2; |
emilmont | 1:fdd22bb7aa52 | 701 | T1 = pSrc16[(i1 * 2u) + 1] >> 2; |
emilmont | 1:fdd22bb7aa52 | 702 | |
emilmont | 1:fdd22bb7aa52 | 703 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 704 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 705 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 706 | pSrc16[(i1 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 707 | |
emilmont | 1:fdd22bb7aa52 | 708 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 709 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 710 | /* U0 = yd, U1 = xd */ |
emilmont | 1:fdd22bb7aa52 | 711 | U0 = pSrc16[i3 * 2u] >> 2; |
emilmont | 1:fdd22bb7aa52 | 712 | U1 = pSrc16[(i3 * 2u) + 1] >> 2; |
emilmont | 1:fdd22bb7aa52 | 713 | /* T0 = yb-yd */ |
emilmont | 1:fdd22bb7aa52 | 714 | T0 = __SSAT(T0 - U0, 16); |
emilmont | 1:fdd22bb7aa52 | 715 | /* T1 = xb-xd */ |
emilmont | 1:fdd22bb7aa52 | 716 | T1 = __SSAT(T1 - U1, 16); |
emilmont | 1:fdd22bb7aa52 | 717 | |
emilmont | 1:fdd22bb7aa52 | 718 | /* R1 = (ya-yc) + (xb- xd), R0 = (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 719 | R0 = (short) __SSAT((q31_t) (S0 - T1), 16); |
emilmont | 1:fdd22bb7aa52 | 720 | R1 = (short) __SSAT((q31_t) (S1 + T0), 16); |
emilmont | 1:fdd22bb7aa52 | 721 | |
emilmont | 1:fdd22bb7aa52 | 722 | /* S1 = (ya-yc) - (xb- xd), S0 = (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 723 | S0 = (short) __SSAT(((q31_t) S0 + T1), 16u); |
emilmont | 1:fdd22bb7aa52 | 724 | S1 = (short) __SSAT(((q31_t) S1 - T0), 16u); |
emilmont | 1:fdd22bb7aa52 | 725 | |
emilmont | 1:fdd22bb7aa52 | 726 | /* co1 & si1 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 727 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 728 | Si1 = pCoef16[(ic * 2u) + 1]; |
emilmont | 1:fdd22bb7aa52 | 729 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 730 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 731 | out1 = (short) ((Si1 * S1 + Co1 * S0) >> 16); |
emilmont | 1:fdd22bb7aa52 | 732 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 733 | out2 = (short) ((-Si1 * S0 + Co1 * S1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 734 | |
emilmont | 1:fdd22bb7aa52 | 735 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 736 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 737 | pSrc16[(i2 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 738 | |
emilmont | 1:fdd22bb7aa52 | 739 | /* Co3 & si3 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 740 | Co3 = pCoef16[3u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 741 | Si3 = pCoef16[(3u * (ic * 2u)) + 1]; |
emilmont | 1:fdd22bb7aa52 | 742 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 743 | /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 744 | out1 = (short) ((Si3 * R1 + Co3 * R0) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 745 | /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 746 | out2 = (short) ((-Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 747 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 748 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 749 | pSrc16[(i3 * 2u) + 1] = out2; |
emilmont | 1:fdd22bb7aa52 | 750 | |
emilmont | 1:fdd22bb7aa52 | 751 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 752 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 753 | |
emilmont | 1:fdd22bb7aa52 | 754 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 755 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 756 | |
emilmont | 1:fdd22bb7aa52 | 757 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 758 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 759 | |
emilmont | 1:fdd22bb7aa52 | 760 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 761 | |
emilmont | 1:fdd22bb7aa52 | 762 | |
emilmont | 1:fdd22bb7aa52 | 763 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 764 | |
emilmont | 1:fdd22bb7aa52 | 765 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 766 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 767 | |
emilmont | 1:fdd22bb7aa52 | 768 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 769 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 770 | { |
emilmont | 1:fdd22bb7aa52 | 771 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 772 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 773 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 774 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 775 | |
emilmont | 1:fdd22bb7aa52 | 776 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 777 | { |
emilmont | 1:fdd22bb7aa52 | 778 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 779 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 780 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 781 | Co2 = pCoef16[2u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 782 | Si2 = pCoef16[(2u * (ic * 2u)) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 783 | Co3 = pCoef16[3u * (ic * 2u)]; |
emilmont | 1:fdd22bb7aa52 | 784 | Si3 = pCoef16[(3u * (ic * 2u)) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 785 | |
emilmont | 1:fdd22bb7aa52 | 786 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 787 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 788 | |
emilmont | 1:fdd22bb7aa52 | 789 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 790 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 791 | { |
emilmont | 1:fdd22bb7aa52 | 792 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 793 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 794 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 795 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 796 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 797 | |
emilmont | 1:fdd22bb7aa52 | 798 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 799 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 800 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 801 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 802 | |
emilmont | 1:fdd22bb7aa52 | 803 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 804 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 805 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 806 | |
emilmont | 1:fdd22bb7aa52 | 807 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 808 | R0 = __SSAT(T0 + S0, 16); |
emilmont | 1:fdd22bb7aa52 | 809 | R1 = __SSAT(T1 + S1, 16); |
emilmont | 1:fdd22bb7aa52 | 810 | |
emilmont | 1:fdd22bb7aa52 | 811 | /* S0 = (ya - yc), S1 =(xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 812 | S0 = __SSAT(T0 - S0, 16); |
emilmont | 1:fdd22bb7aa52 | 813 | S1 = __SSAT(T1 - S1, 16); |
emilmont | 1:fdd22bb7aa52 | 814 | |
emilmont | 1:fdd22bb7aa52 | 815 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 816 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 817 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 818 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 819 | |
emilmont | 1:fdd22bb7aa52 | 820 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 821 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 822 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 823 | |
emilmont | 1:fdd22bb7aa52 | 824 | |
emilmont | 1:fdd22bb7aa52 | 825 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 826 | T0 = __SSAT(T0 + U0, 16); |
emilmont | 1:fdd22bb7aa52 | 827 | T1 = __SSAT(T1 + U1, 16); |
emilmont | 1:fdd22bb7aa52 | 828 | |
emilmont | 1:fdd22bb7aa52 | 829 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 830 | |
emilmont | 1:fdd22bb7aa52 | 831 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 832 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 833 | out1 = ((R0 >> 1u) + (T0 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 834 | out2 = ((R1 >> 1u) + (T1 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 835 | |
emilmont | 1:fdd22bb7aa52 | 836 | pSrc16[i0 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 837 | pSrc16[(2u * i0) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 838 | |
emilmont | 1:fdd22bb7aa52 | 839 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 840 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 841 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 842 | |
emilmont | 1:fdd22bb7aa52 | 843 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 844 | out1 = (short) ((Co2 * R0 + Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 845 | |
emilmont | 1:fdd22bb7aa52 | 846 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 847 | out2 = (short) ((-Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 848 | |
emilmont | 1:fdd22bb7aa52 | 849 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 850 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 851 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 852 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 853 | |
emilmont | 1:fdd22bb7aa52 | 854 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 855 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 856 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 857 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 858 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 859 | |
emilmont | 1:fdd22bb7aa52 | 860 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 861 | |
emilmont | 1:fdd22bb7aa52 | 862 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 863 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 864 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 865 | |
emilmont | 1:fdd22bb7aa52 | 866 | /* T0 = yb-yd, T1 = xb-xd */ |
emilmont | 1:fdd22bb7aa52 | 867 | T0 = __SSAT(T0 - U0, 16); |
emilmont | 1:fdd22bb7aa52 | 868 | T1 = __SSAT(T1 - U1, 16); |
emilmont | 1:fdd22bb7aa52 | 869 | |
emilmont | 1:fdd22bb7aa52 | 870 | /* R0 = (ya-yc) + (xb- xd), R1 = (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 871 | R0 = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 872 | R1 = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 873 | |
emilmont | 1:fdd22bb7aa52 | 874 | /* S0 = (ya-yc) - (xb- xd), S1 = (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 875 | S0 = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 876 | S1 = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 877 | |
emilmont | 1:fdd22bb7aa52 | 878 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 879 | out1 = (short) ((Co1 * S0 + Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 880 | |
emilmont | 1:fdd22bb7aa52 | 881 | out2 = (short) ((-Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 882 | |
emilmont | 1:fdd22bb7aa52 | 883 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 884 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 885 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 886 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 887 | |
emilmont | 1:fdd22bb7aa52 | 888 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 889 | out1 = (short) ((Si3 * R1 + Co3 * R0) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 890 | |
emilmont | 1:fdd22bb7aa52 | 891 | out2 = (short) ((-Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 892 | /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 893 | /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 894 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 895 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 896 | } |
emilmont | 1:fdd22bb7aa52 | 897 | } |
emilmont | 1:fdd22bb7aa52 | 898 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 899 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 900 | } |
emilmont | 1:fdd22bb7aa52 | 901 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 902 | |
emilmont | 1:fdd22bb7aa52 | 903 | |
emilmont | 1:fdd22bb7aa52 | 904 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 905 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 906 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 907 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 908 | |
emilmont | 1:fdd22bb7aa52 | 909 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 910 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 911 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 912 | |
emilmont | 1:fdd22bb7aa52 | 913 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 914 | |
emilmont | 1:fdd22bb7aa52 | 915 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 916 | for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 917 | { |
emilmont | 1:fdd22bb7aa52 | 918 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 919 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 920 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 921 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 922 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 923 | |
emilmont | 1:fdd22bb7aa52 | 924 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 925 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 926 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 927 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 928 | |
emilmont | 1:fdd22bb7aa52 | 929 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 930 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 931 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 932 | |
emilmont | 1:fdd22bb7aa52 | 933 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 934 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 935 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 936 | |
emilmont | 1:fdd22bb7aa52 | 937 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 938 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 939 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 940 | |
emilmont | 1:fdd22bb7aa52 | 941 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 942 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 943 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 944 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 945 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 946 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 947 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 948 | |
emilmont | 1:fdd22bb7aa52 | 949 | /* T0 = (yb + yd), T1 = (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 950 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 951 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 952 | |
emilmont | 1:fdd22bb7aa52 | 953 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 954 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 955 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 956 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 957 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 958 | |
emilmont | 1:fdd22bb7aa52 | 959 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 960 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 961 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 962 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 963 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 964 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 965 | |
emilmont | 1:fdd22bb7aa52 | 966 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 967 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 968 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 969 | pSrc16[i1 * 2u] = R0; |
emilmont | 1:fdd22bb7aa52 | 970 | pSrc16[(i1 * 2u) + 1u] = R1; |
emilmont | 1:fdd22bb7aa52 | 971 | |
emilmont | 1:fdd22bb7aa52 | 972 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 973 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 974 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 975 | /* T0 = (yb - yd), T1 = (xb - xd) */ |
emilmont | 1:fdd22bb7aa52 | 976 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 977 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 978 | |
emilmont | 1:fdd22bb7aa52 | 979 | /* writing the butterfly processed i0 + fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 980 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 981 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 982 | pSrc16[i2 * 2u] = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 983 | pSrc16[(i2 * 2u) + 1u] = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 984 | |
emilmont | 1:fdd22bb7aa52 | 985 | /* writing the butterfly processed i0 + 3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 986 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 987 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 988 | pSrc16[i3 * 2u] = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 989 | pSrc16[(i3 * 2u) + 1u] = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 990 | |
emilmont | 1:fdd22bb7aa52 | 991 | } |
emilmont | 1:fdd22bb7aa52 | 992 | |
emilmont | 1:fdd22bb7aa52 | 993 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 994 | |
emilmont | 1:fdd22bb7aa52 | 995 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 996 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 997 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 998 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 999 | |
emilmont | 1:fdd22bb7aa52 | 1000 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 1001 | |
emilmont | 1:fdd22bb7aa52 | 1002 | } |
emilmont | 1:fdd22bb7aa52 | 1003 | |
emilmont | 1:fdd22bb7aa52 | 1004 | |
emilmont | 1:fdd22bb7aa52 | 1005 | /** |
emilmont | 1:fdd22bb7aa52 | 1006 | * @brief Core function for the Q15 CIFFT butterfly process. |
emilmont | 1:fdd22bb7aa52 | 1007 | * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type. |
emilmont | 1:fdd22bb7aa52 | 1008 | * @param[in] fftLen length of the FFT. |
emilmont | 1:fdd22bb7aa52 | 1009 | * @param[in] *pCoef16 points to twiddle coefficient buffer. |
emilmont | 1:fdd22bb7aa52 | 1010 | * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table. |
emilmont | 1:fdd22bb7aa52 | 1011 | * @return none. |
emilmont | 1:fdd22bb7aa52 | 1012 | */ |
emilmont | 1:fdd22bb7aa52 | 1013 | |
emilmont | 1:fdd22bb7aa52 | 1014 | /* |
emilmont | 1:fdd22bb7aa52 | 1015 | * Radix-4 IFFT algorithm used is : |
emilmont | 1:fdd22bb7aa52 | 1016 | * |
emilmont | 1:fdd22bb7aa52 | 1017 | * CIFFT uses same twiddle coefficients as CFFT function |
emilmont | 1:fdd22bb7aa52 | 1018 | * x[k] = x[n] + (j)k * x[n + fftLen/4] + (-1)k * x[n+fftLen/2] + (-j)k * x[n+3*fftLen/4] |
emilmont | 1:fdd22bb7aa52 | 1019 | * |
emilmont | 1:fdd22bb7aa52 | 1020 | * |
emilmont | 1:fdd22bb7aa52 | 1021 | * IFFT is implemented with following changes in equations from FFT |
emilmont | 1:fdd22bb7aa52 | 1022 | * |
emilmont | 1:fdd22bb7aa52 | 1023 | * Input real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 1024 | * x(n) = xa + j * ya |
emilmont | 1:fdd22bb7aa52 | 1025 | * x(n+N/4 ) = xb + j * yb |
emilmont | 1:fdd22bb7aa52 | 1026 | * x(n+N/2 ) = xc + j * yc |
emilmont | 1:fdd22bb7aa52 | 1027 | * x(n+3N 4) = xd + j * yd |
emilmont | 1:fdd22bb7aa52 | 1028 | * |
emilmont | 1:fdd22bb7aa52 | 1029 | * |
emilmont | 1:fdd22bb7aa52 | 1030 | * Output real and imaginary data: |
emilmont | 1:fdd22bb7aa52 | 1031 | * x(4r) = xa'+ j * ya' |
emilmont | 1:fdd22bb7aa52 | 1032 | * x(4r+1) = xb'+ j * yb' |
emilmont | 1:fdd22bb7aa52 | 1033 | * x(4r+2) = xc'+ j * yc' |
emilmont | 1:fdd22bb7aa52 | 1034 | * x(4r+3) = xd'+ j * yd' |
emilmont | 1:fdd22bb7aa52 | 1035 | * |
emilmont | 1:fdd22bb7aa52 | 1036 | * |
emilmont | 1:fdd22bb7aa52 | 1037 | * Twiddle factors for radix-4 IFFT: |
emilmont | 1:fdd22bb7aa52 | 1038 | * Wn = co1 + j * (si1) |
emilmont | 1:fdd22bb7aa52 | 1039 | * W2n = co2 + j * (si2) |
emilmont | 1:fdd22bb7aa52 | 1040 | * W3n = co3 + j * (si3) |
emilmont | 1:fdd22bb7aa52 | 1041 | |
emilmont | 1:fdd22bb7aa52 | 1042 | * The real and imaginary output values for the radix-4 butterfly are |
emilmont | 1:fdd22bb7aa52 | 1043 | * xa' = xa + xb + xc + xd |
emilmont | 1:fdd22bb7aa52 | 1044 | * ya' = ya + yb + yc + yd |
emilmont | 1:fdd22bb7aa52 | 1045 | * xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 1046 | * yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) |
emilmont | 1:fdd22bb7aa52 | 1047 | * xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 1048 | * yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) |
emilmont | 1:fdd22bb7aa52 | 1049 | * xd' = (xa+yb-xc-yd)* co3 - (ya-xb-yc+xd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 1050 | * yd' = (ya-xb-yc+xd)* co3 + (xa+yb-xc-yd)* (si3) |
emilmont | 1:fdd22bb7aa52 | 1051 | * |
emilmont | 1:fdd22bb7aa52 | 1052 | */ |
emilmont | 1:fdd22bb7aa52 | 1053 | |
emilmont | 1:fdd22bb7aa52 | 1054 | void arm_radix4_butterfly_inverse_q15( |
emilmont | 1:fdd22bb7aa52 | 1055 | q15_t * pSrc16, |
emilmont | 1:fdd22bb7aa52 | 1056 | uint32_t fftLen, |
emilmont | 1:fdd22bb7aa52 | 1057 | q15_t * pCoef16, |
emilmont | 1:fdd22bb7aa52 | 1058 | uint32_t twidCoefModifier) |
emilmont | 1:fdd22bb7aa52 | 1059 | { |
emilmont | 1:fdd22bb7aa52 | 1060 | |
emilmont | 1:fdd22bb7aa52 | 1061 | #ifndef ARM_MATH_CM0 |
emilmont | 1:fdd22bb7aa52 | 1062 | |
emilmont | 1:fdd22bb7aa52 | 1063 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
emilmont | 1:fdd22bb7aa52 | 1064 | |
emilmont | 1:fdd22bb7aa52 | 1065 | q31_t R, S, T, U; |
emilmont | 1:fdd22bb7aa52 | 1066 | q31_t C1, C2, C3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 1067 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 1068 | q15_t in; |
emilmont | 1:fdd22bb7aa52 | 1069 | |
emilmont | 1:fdd22bb7aa52 | 1070 | q15_t *ptr1; |
emilmont | 1:fdd22bb7aa52 | 1071 | |
emilmont | 1:fdd22bb7aa52 | 1072 | |
emilmont | 1:fdd22bb7aa52 | 1073 | |
emilmont | 1:fdd22bb7aa52 | 1074 | q31_t xaya, xbyb, xcyc, xdyd; |
emilmont | 1:fdd22bb7aa52 | 1075 | |
emilmont | 1:fdd22bb7aa52 | 1076 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 1077 | |
emilmont | 1:fdd22bb7aa52 | 1078 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 1079 | |
emilmont | 1:fdd22bb7aa52 | 1080 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 1081 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 1082 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1083 | |
emilmont | 1:fdd22bb7aa52 | 1084 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1085 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1086 | |
emilmont | 1:fdd22bb7aa52 | 1087 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 1088 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1089 | |
emilmont | 1:fdd22bb7aa52 | 1090 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 1091 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 1092 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 1093 | |
emilmont | 1:fdd22bb7aa52 | 1094 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 1095 | |
emilmont | 1:fdd22bb7aa52 | 1096 | /* start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1097 | do |
emilmont | 1:fdd22bb7aa52 | 1098 | { |
emilmont | 1:fdd22bb7aa52 | 1099 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1100 | |
emilmont | 1:fdd22bb7aa52 | 1101 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1102 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1103 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1104 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1105 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1106 | |
emilmont | 1:fdd22bb7aa52 | 1107 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1108 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1109 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 1110 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1111 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1112 | |
emilmont | 1:fdd22bb7aa52 | 1113 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1114 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 1115 | in = ((int16_t) (S & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1116 | S = ((S >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1117 | |
emilmont | 1:fdd22bb7aa52 | 1118 | /* R = packed((ya + yc), (xa + xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 1119 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1120 | |
emilmont | 1:fdd22bb7aa52 | 1121 | /* S = packed((ya - yc), (xa - xc) ) */ |
emilmont | 1:fdd22bb7aa52 | 1122 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1123 | |
emilmont | 1:fdd22bb7aa52 | 1124 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1125 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1126 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1127 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1128 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1129 | |
emilmont | 1:fdd22bb7aa52 | 1130 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1131 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1132 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1133 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1134 | |
emilmont | 1:fdd22bb7aa52 | 1135 | /* T = packed((yb + yd), (xb + xd) ) */ |
emilmont | 1:fdd22bb7aa52 | 1136 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1137 | |
emilmont | 1:fdd22bb7aa52 | 1138 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1139 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1140 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1141 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1142 | |
emilmont | 1:fdd22bb7aa52 | 1143 | /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1144 | R = __QSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1145 | |
emilmont | 1:fdd22bb7aa52 | 1146 | /* co2 & si2 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1147 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1148 | |
emilmont | 1:fdd22bb7aa52 | 1149 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1150 | |
emilmont | 1:fdd22bb7aa52 | 1151 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1152 | out1 = __SMUSD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1153 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1154 | out2 = __SMUADX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 1155 | |
emilmont | 1:fdd22bb7aa52 | 1156 | #else |
emilmont | 1:fdd22bb7aa52 | 1157 | |
emilmont | 1:fdd22bb7aa52 | 1158 | /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1159 | out1 = __SMUADX(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1160 | /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1161 | out2 = __SMUSD(__QSUB16(0, C2), R); |
emilmont | 1:fdd22bb7aa52 | 1162 | |
emilmont | 1:fdd22bb7aa52 | 1163 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1164 | |
emilmont | 1:fdd22bb7aa52 | 1165 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1166 | /* T = packed(yb, xb) */ |
emilmont | 1:fdd22bb7aa52 | 1167 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1168 | in = ((int16_t) (T & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1169 | T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1170 | |
emilmont | 1:fdd22bb7aa52 | 1171 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1172 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1173 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 1174 | (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1175 | |
emilmont | 1:fdd22bb7aa52 | 1176 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1177 | /* U = packed(yd, xd) */ |
emilmont | 1:fdd22bb7aa52 | 1178 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1179 | in = ((int16_t) (U & 0xFFFF)) >> 2; |
emilmont | 1:fdd22bb7aa52 | 1180 | U = ((U >> 2) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1181 | |
emilmont | 1:fdd22bb7aa52 | 1182 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1183 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1184 | |
emilmont | 1:fdd22bb7aa52 | 1185 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1186 | |
emilmont | 1:fdd22bb7aa52 | 1187 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1188 | R = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1189 | /* S = packed((ya-yc) + (xb- xd), (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1190 | S = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1191 | |
emilmont | 1:fdd22bb7aa52 | 1192 | #else |
emilmont | 1:fdd22bb7aa52 | 1193 | |
emilmont | 1:fdd22bb7aa52 | 1194 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1195 | R = __QASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1196 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1197 | S = __QSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1198 | |
emilmont | 1:fdd22bb7aa52 | 1199 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1200 | |
emilmont | 1:fdd22bb7aa52 | 1201 | /* co1 & si1 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1202 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1203 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1204 | |
emilmont | 1:fdd22bb7aa52 | 1205 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1206 | |
emilmont | 1:fdd22bb7aa52 | 1207 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1208 | out1 = __SMUSD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1209 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1210 | out2 = __SMUADX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 1211 | |
emilmont | 1:fdd22bb7aa52 | 1212 | #else |
emilmont | 1:fdd22bb7aa52 | 1213 | |
emilmont | 1:fdd22bb7aa52 | 1214 | /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1215 | out1 = __SMUADX(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1216 | /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1217 | out2 = __SMUSD(__QSUB16(0, C1), S); |
emilmont | 1:fdd22bb7aa52 | 1218 | |
emilmont | 1:fdd22bb7aa52 | 1219 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1220 | |
emilmont | 1:fdd22bb7aa52 | 1221 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1222 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 1223 | ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1224 | |
emilmont | 1:fdd22bb7aa52 | 1225 | |
emilmont | 1:fdd22bb7aa52 | 1226 | /* co3 & si3 are read from SIMD Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1227 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1228 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1229 | |
emilmont | 1:fdd22bb7aa52 | 1230 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1231 | |
emilmont | 1:fdd22bb7aa52 | 1232 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1233 | out1 = __SMUSD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1234 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1235 | out2 = __SMUADX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 1236 | |
emilmont | 1:fdd22bb7aa52 | 1237 | #else |
emilmont | 1:fdd22bb7aa52 | 1238 | |
emilmont | 1:fdd22bb7aa52 | 1239 | /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1240 | out1 = __SMUADX(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1241 | /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1242 | out2 = __SMUSD(__QSUB16(0, C3), R); |
emilmont | 1:fdd22bb7aa52 | 1243 | |
emilmont | 1:fdd22bb7aa52 | 1244 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1245 | |
emilmont | 1:fdd22bb7aa52 | 1246 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1247 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 1248 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1249 | |
emilmont | 1:fdd22bb7aa52 | 1250 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1251 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1252 | |
emilmont | 1:fdd22bb7aa52 | 1253 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 1254 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 1255 | |
emilmont | 1:fdd22bb7aa52 | 1256 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1257 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 1258 | |
emilmont | 1:fdd22bb7aa52 | 1259 | /* end of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1260 | |
emilmont | 1:fdd22bb7aa52 | 1261 | |
emilmont | 1:fdd22bb7aa52 | 1262 | /* start of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1263 | |
emilmont | 1:fdd22bb7aa52 | 1264 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1265 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1266 | |
emilmont | 1:fdd22bb7aa52 | 1267 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1268 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 1269 | { |
emilmont | 1:fdd22bb7aa52 | 1270 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1271 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1272 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1273 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1274 | |
emilmont | 1:fdd22bb7aa52 | 1275 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 1276 | { |
emilmont | 1:fdd22bb7aa52 | 1277 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 1278 | C1 = _SIMD32_OFFSET(pCoef16 + (2u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1279 | C2 = _SIMD32_OFFSET(pCoef16 + (4u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1280 | C3 = _SIMD32_OFFSET(pCoef16 + (6u * ic)); |
emilmont | 1:fdd22bb7aa52 | 1281 | |
emilmont | 1:fdd22bb7aa52 | 1282 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1283 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1284 | |
emilmont | 1:fdd22bb7aa52 | 1285 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1286 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1287 | { |
emilmont | 1:fdd22bb7aa52 | 1288 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1289 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1290 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1291 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1292 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1293 | |
emilmont | 1:fdd22bb7aa52 | 1294 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1295 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1296 | T = _SIMD32_OFFSET(pSrc16 + (2u * i0)); |
emilmont | 1:fdd22bb7aa52 | 1297 | |
emilmont | 1:fdd22bb7aa52 | 1298 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1299 | S = _SIMD32_OFFSET(pSrc16 + (2u * i2)); |
emilmont | 1:fdd22bb7aa52 | 1300 | |
emilmont | 1:fdd22bb7aa52 | 1301 | /* R = packed( (ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1302 | R = __QADD16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1303 | |
emilmont | 1:fdd22bb7aa52 | 1304 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1305 | S = __QSUB16(T, S); |
emilmont | 1:fdd22bb7aa52 | 1306 | |
emilmont | 1:fdd22bb7aa52 | 1307 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1308 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1309 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1310 | |
emilmont | 1:fdd22bb7aa52 | 1311 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1312 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1313 | |
emilmont | 1:fdd22bb7aa52 | 1314 | /* T = packed( (yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1315 | T = __QADD16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1316 | |
emilmont | 1:fdd22bb7aa52 | 1317 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1318 | |
emilmont | 1:fdd22bb7aa52 | 1319 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1320 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1321 | out1 = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1322 | in = ((int16_t) (out1 & 0xFFFF)) >> 1; |
emilmont | 1:fdd22bb7aa52 | 1323 | out1 = ((out1 >> 1) & 0xFFFF0000) | (in & 0xFFFF); |
emilmont | 1:fdd22bb7aa52 | 1324 | _SIMD32_OFFSET(pSrc16 + (2u * i0)) = out1; |
emilmont | 1:fdd22bb7aa52 | 1325 | |
emilmont | 1:fdd22bb7aa52 | 1326 | /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1327 | R = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1328 | |
emilmont | 1:fdd22bb7aa52 | 1329 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1330 | |
emilmont | 1:fdd22bb7aa52 | 1331 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1332 | out1 = __SMUSD(C2, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1333 | |
emilmont | 1:fdd22bb7aa52 | 1334 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1335 | out2 = __SMUADX(C2, R); |
emilmont | 1:fdd22bb7aa52 | 1336 | |
emilmont | 1:fdd22bb7aa52 | 1337 | #else |
emilmont | 1:fdd22bb7aa52 | 1338 | |
emilmont | 1:fdd22bb7aa52 | 1339 | /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1340 | out1 = __SMUADX(R, C2) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1341 | |
emilmont | 1:fdd22bb7aa52 | 1342 | /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1343 | out2 = __SMUSD(__QSUB16(0, C2), R); |
emilmont | 1:fdd22bb7aa52 | 1344 | |
emilmont | 1:fdd22bb7aa52 | 1345 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1346 | |
emilmont | 1:fdd22bb7aa52 | 1347 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1348 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1349 | T = _SIMD32_OFFSET(pSrc16 + (2u * i1)); |
emilmont | 1:fdd22bb7aa52 | 1350 | |
emilmont | 1:fdd22bb7aa52 | 1351 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1352 | /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1353 | /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1354 | _SIMD32_OFFSET(pSrc16 + (2u * i1)) = |
emilmont | 1:fdd22bb7aa52 | 1355 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1356 | |
emilmont | 1:fdd22bb7aa52 | 1357 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1358 | |
emilmont | 1:fdd22bb7aa52 | 1359 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1360 | U = _SIMD32_OFFSET(pSrc16 + (2u * i3)); |
emilmont | 1:fdd22bb7aa52 | 1361 | |
emilmont | 1:fdd22bb7aa52 | 1362 | /* T = packed(yb-yd, xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1363 | T = __QSUB16(T, U); |
emilmont | 1:fdd22bb7aa52 | 1364 | |
emilmont | 1:fdd22bb7aa52 | 1365 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1366 | |
emilmont | 1:fdd22bb7aa52 | 1367 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1368 | R = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1369 | |
emilmont | 1:fdd22bb7aa52 | 1370 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1371 | S = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1372 | |
emilmont | 1:fdd22bb7aa52 | 1373 | |
emilmont | 1:fdd22bb7aa52 | 1374 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1375 | out1 = __SMUSD(C1, S) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1376 | out2 = __SMUADX(C1, S); |
emilmont | 1:fdd22bb7aa52 | 1377 | |
emilmont | 1:fdd22bb7aa52 | 1378 | #else |
emilmont | 1:fdd22bb7aa52 | 1379 | |
emilmont | 1:fdd22bb7aa52 | 1380 | /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1381 | R = __SHASX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1382 | |
emilmont | 1:fdd22bb7aa52 | 1383 | /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */ |
emilmont | 1:fdd22bb7aa52 | 1384 | S = __SHSAX(S, T); |
emilmont | 1:fdd22bb7aa52 | 1385 | |
emilmont | 1:fdd22bb7aa52 | 1386 | |
emilmont | 1:fdd22bb7aa52 | 1387 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1388 | out1 = __SMUADX(S, C1) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1389 | out2 = __SMUSD(__QSUB16(0, C1), S); |
emilmont | 1:fdd22bb7aa52 | 1390 | |
emilmont | 1:fdd22bb7aa52 | 1391 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1392 | |
emilmont | 1:fdd22bb7aa52 | 1393 | /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1394 | /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1395 | _SIMD32_OFFSET(pSrc16 + (2u * i2)) = |
emilmont | 1:fdd22bb7aa52 | 1396 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1397 | |
emilmont | 1:fdd22bb7aa52 | 1398 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1399 | |
emilmont | 1:fdd22bb7aa52 | 1400 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1401 | |
emilmont | 1:fdd22bb7aa52 | 1402 | out1 = __SMUSD(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1403 | out2 = __SMUADX(C3, R); |
emilmont | 1:fdd22bb7aa52 | 1404 | |
emilmont | 1:fdd22bb7aa52 | 1405 | #else |
emilmont | 1:fdd22bb7aa52 | 1406 | |
emilmont | 1:fdd22bb7aa52 | 1407 | out1 = __SMUADX(C3, R) >> 16u; |
emilmont | 1:fdd22bb7aa52 | 1408 | out2 = __SMUSD(__QSUB16(0, C3), R); |
emilmont | 1:fdd22bb7aa52 | 1409 | |
emilmont | 1:fdd22bb7aa52 | 1410 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1411 | |
emilmont | 1:fdd22bb7aa52 | 1412 | /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1413 | /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1414 | _SIMD32_OFFSET(pSrc16 + (2u * i3)) = |
emilmont | 1:fdd22bb7aa52 | 1415 | ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF); |
emilmont | 1:fdd22bb7aa52 | 1416 | } |
emilmont | 1:fdd22bb7aa52 | 1417 | } |
emilmont | 1:fdd22bb7aa52 | 1418 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1419 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1420 | } |
emilmont | 1:fdd22bb7aa52 | 1421 | /* end of middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1422 | |
emilmont | 1:fdd22bb7aa52 | 1423 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1424 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1425 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1426 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1427 | |
emilmont | 1:fdd22bb7aa52 | 1428 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 1429 | j = fftLen >> 2; |
emilmont | 1:fdd22bb7aa52 | 1430 | |
emilmont | 1:fdd22bb7aa52 | 1431 | ptr1 = &pSrc16[0]; |
emilmont | 1:fdd22bb7aa52 | 1432 | |
emilmont | 1:fdd22bb7aa52 | 1433 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1434 | |
emilmont | 1:fdd22bb7aa52 | 1435 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1436 | do |
emilmont | 1:fdd22bb7aa52 | 1437 | { |
emilmont | 1:fdd22bb7aa52 | 1438 | /* Read xa (real), ya(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1439 | xaya = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1440 | |
emilmont | 1:fdd22bb7aa52 | 1441 | /* Read xb (real), yb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1442 | xbyb = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1443 | |
emilmont | 1:fdd22bb7aa52 | 1444 | /* Read xc (real), yc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1445 | xcyc = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1446 | |
emilmont | 1:fdd22bb7aa52 | 1447 | /* Read xd (real), yd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1448 | xdyd = *__SIMD32(ptr1)++; |
emilmont | 1:fdd22bb7aa52 | 1449 | |
emilmont | 1:fdd22bb7aa52 | 1450 | /* R = packed((ya + yc), (xa + xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1451 | R = __QADD16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 1452 | |
emilmont | 1:fdd22bb7aa52 | 1453 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1454 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1455 | |
emilmont | 1:fdd22bb7aa52 | 1456 | /* pointer updation for writing */ |
emilmont | 1:fdd22bb7aa52 | 1457 | ptr1 = ptr1 - 8u; |
emilmont | 1:fdd22bb7aa52 | 1458 | |
emilmont | 1:fdd22bb7aa52 | 1459 | |
emilmont | 1:fdd22bb7aa52 | 1460 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1461 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1462 | *__SIMD32(ptr1)++ = __SHADD16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1463 | |
emilmont | 1:fdd22bb7aa52 | 1464 | /* T = packed((yb + yd), (xb + xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1465 | T = __QADD16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1466 | |
emilmont | 1:fdd22bb7aa52 | 1467 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1468 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1469 | *__SIMD32(ptr1)++ = __SHSUB16(R, T); |
emilmont | 1:fdd22bb7aa52 | 1470 | |
emilmont | 1:fdd22bb7aa52 | 1471 | /* S = packed((ya - yc), (xa - xc)) */ |
emilmont | 1:fdd22bb7aa52 | 1472 | S = __QSUB16(xaya, xcyc); |
emilmont | 1:fdd22bb7aa52 | 1473 | |
emilmont | 1:fdd22bb7aa52 | 1474 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1475 | /* T = packed( (yb - yd), (xb - xd)) */ |
emilmont | 1:fdd22bb7aa52 | 1476 | U = __QSUB16(xbyb, xdyd); |
emilmont | 1:fdd22bb7aa52 | 1477 | |
emilmont | 1:fdd22bb7aa52 | 1478 | #ifndef ARM_MATH_BIG_ENDIAN |
emilmont | 1:fdd22bb7aa52 | 1479 | |
emilmont | 1:fdd22bb7aa52 | 1480 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1481 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1482 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1483 | |
emilmont | 1:fdd22bb7aa52 | 1484 | |
emilmont | 1:fdd22bb7aa52 | 1485 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1486 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1487 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1488 | |
emilmont | 1:fdd22bb7aa52 | 1489 | #else |
emilmont | 1:fdd22bb7aa52 | 1490 | |
emilmont | 1:fdd22bb7aa52 | 1491 | /* xb' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1492 | /* yb' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1493 | *__SIMD32(ptr1)++ = __SHSAX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1494 | |
emilmont | 1:fdd22bb7aa52 | 1495 | |
emilmont | 1:fdd22bb7aa52 | 1496 | /* xd' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1497 | /* yd' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1498 | *__SIMD32(ptr1)++ = __SHASX(S, U); |
emilmont | 1:fdd22bb7aa52 | 1499 | |
emilmont | 1:fdd22bb7aa52 | 1500 | |
emilmont | 1:fdd22bb7aa52 | 1501 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
emilmont | 1:fdd22bb7aa52 | 1502 | |
emilmont | 1:fdd22bb7aa52 | 1503 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1504 | |
emilmont | 1:fdd22bb7aa52 | 1505 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1506 | |
emilmont | 1:fdd22bb7aa52 | 1507 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1508 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1509 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1510 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1511 | |
emilmont | 1:fdd22bb7aa52 | 1512 | |
emilmont | 1:fdd22bb7aa52 | 1513 | #else |
emilmont | 1:fdd22bb7aa52 | 1514 | |
emilmont | 1:fdd22bb7aa52 | 1515 | /* Run the below code for Cortex-M0 */ |
emilmont | 1:fdd22bb7aa52 | 1516 | |
emilmont | 1:fdd22bb7aa52 | 1517 | q15_t R0, R1, S0, S1, T0, T1, U0, U1; |
emilmont | 1:fdd22bb7aa52 | 1518 | q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2; |
emilmont | 1:fdd22bb7aa52 | 1519 | uint32_t n1, n2, ic, i0, i1, i2, i3, j, k; |
emilmont | 1:fdd22bb7aa52 | 1520 | |
emilmont | 1:fdd22bb7aa52 | 1521 | /* Total process is divided into three stages */ |
emilmont | 1:fdd22bb7aa52 | 1522 | |
emilmont | 1:fdd22bb7aa52 | 1523 | /* process first stage, middle stages, & last stage */ |
emilmont | 1:fdd22bb7aa52 | 1524 | |
emilmont | 1:fdd22bb7aa52 | 1525 | /* Initializations for the first stage */ |
emilmont | 1:fdd22bb7aa52 | 1526 | n2 = fftLen; |
emilmont | 1:fdd22bb7aa52 | 1527 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1528 | |
emilmont | 1:fdd22bb7aa52 | 1529 | /* n2 = fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1530 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1531 | |
emilmont | 1:fdd22bb7aa52 | 1532 | /* Index for twiddle coefficient */ |
emilmont | 1:fdd22bb7aa52 | 1533 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1534 | |
emilmont | 1:fdd22bb7aa52 | 1535 | /* Index for input read and output write */ |
emilmont | 1:fdd22bb7aa52 | 1536 | i0 = 0u; |
emilmont | 1:fdd22bb7aa52 | 1537 | |
emilmont | 1:fdd22bb7aa52 | 1538 | j = n2; |
emilmont | 1:fdd22bb7aa52 | 1539 | |
emilmont | 1:fdd22bb7aa52 | 1540 | /* Input is in 1.15(q15) format */ |
emilmont | 1:fdd22bb7aa52 | 1541 | |
emilmont | 1:fdd22bb7aa52 | 1542 | /* Start of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1543 | do |
emilmont | 1:fdd22bb7aa52 | 1544 | { |
emilmont | 1:fdd22bb7aa52 | 1545 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1546 | |
emilmont | 1:fdd22bb7aa52 | 1547 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1548 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1549 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1550 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1551 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1552 | |
emilmont | 1:fdd22bb7aa52 | 1553 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1554 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1555 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1556 | T0 = pSrc16[i0 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1557 | T1 = pSrc16[(i0 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1558 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1559 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1560 | S0 = pSrc16[i2 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1561 | S1 = pSrc16[(i2 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1562 | |
emilmont | 1:fdd22bb7aa52 | 1563 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1564 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1565 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1566 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1567 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1568 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1569 | |
emilmont | 1:fdd22bb7aa52 | 1570 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1571 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1572 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1573 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1574 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1575 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1576 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1577 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1578 | U1 = pSrc16[(i3 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1579 | |
emilmont | 1:fdd22bb7aa52 | 1580 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1581 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1582 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1583 | |
emilmont | 1:fdd22bb7aa52 | 1584 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1585 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1586 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1587 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1588 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1589 | |
emilmont | 1:fdd22bb7aa52 | 1590 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc)- (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1591 | R0 = __SSAT(R0 - T0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1592 | R1 = __SSAT(R1 - T1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1593 | /* co2 & si2 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1594 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1595 | Si2 = pCoef16[(2u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1596 | /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1597 | out1 = (short) ((Co2 * R0 - Si2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1598 | /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1599 | out2 = (short) ((Si2 * R0 + Co2 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1600 | |
emilmont | 1:fdd22bb7aa52 | 1601 | /* Reading i0+fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1602 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1603 | /* T0 = yb, T1 = xb */ |
emilmont | 1:fdd22bb7aa52 | 1604 | T0 = pSrc16[i1 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1605 | T1 = pSrc16[(i1 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1606 | |
emilmont | 1:fdd22bb7aa52 | 1607 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1608 | /* writing output(xc', yc') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1609 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1610 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1611 | |
emilmont | 1:fdd22bb7aa52 | 1612 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1613 | /* input is down scale by 4 to avoid overflow */ |
emilmont | 1:fdd22bb7aa52 | 1614 | /* U0 = yd, U1 = xd) */ |
emilmont | 1:fdd22bb7aa52 | 1615 | U0 = pSrc16[i3 * 2u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1616 | U1 = pSrc16[(i3 * 2u) + 1u] >> 2u; |
emilmont | 1:fdd22bb7aa52 | 1617 | |
emilmont | 1:fdd22bb7aa52 | 1618 | /* T0 = yb-yd, T1 = xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1619 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1620 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1621 | /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1622 | R0 = (short) __SSAT((q31_t) (S0 + T1), 16); |
emilmont | 1:fdd22bb7aa52 | 1623 | R1 = (short) __SSAT((q31_t) (S1 - T0), 16); |
emilmont | 1:fdd22bb7aa52 | 1624 | /* S = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1625 | S0 = (short) __SSAT((q31_t) (S0 - T1), 16); |
emilmont | 1:fdd22bb7aa52 | 1626 | S1 = (short) __SSAT((q31_t) (S1 + T0), 16); |
emilmont | 1:fdd22bb7aa52 | 1627 | |
emilmont | 1:fdd22bb7aa52 | 1628 | /* co1 & si1 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1629 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1630 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1631 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1632 | /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1633 | out1 = (short) ((Co1 * S0 - Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1634 | /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1635 | out2 = (short) ((Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1636 | /* writing output(xb', yb') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1637 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1638 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1639 | |
emilmont | 1:fdd22bb7aa52 | 1640 | /* Co3 & si3 are read from Coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 1641 | Co3 = pCoef16[3u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1642 | Si3 = pCoef16[(3u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1643 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1644 | /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1645 | out1 = (short) ((Co3 * R0 - Si3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1646 | /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1647 | out2 = (short) ((Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1648 | /* writing output(xd', yd') in little endian format */ |
emilmont | 1:fdd22bb7aa52 | 1649 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1650 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1651 | |
emilmont | 1:fdd22bb7aa52 | 1652 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1653 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1654 | |
emilmont | 1:fdd22bb7aa52 | 1655 | /* Updating input index */ |
emilmont | 1:fdd22bb7aa52 | 1656 | i0 = i0 + 1u; |
emilmont | 1:fdd22bb7aa52 | 1657 | |
emilmont | 1:fdd22bb7aa52 | 1658 | } while(--j); |
emilmont | 1:fdd22bb7aa52 | 1659 | |
emilmont | 1:fdd22bb7aa52 | 1660 | /* End of first stage process */ |
emilmont | 1:fdd22bb7aa52 | 1661 | |
emilmont | 1:fdd22bb7aa52 | 1662 | /* data is in 4.11(q11) format */ |
emilmont | 1:fdd22bb7aa52 | 1663 | |
emilmont | 1:fdd22bb7aa52 | 1664 | |
emilmont | 1:fdd22bb7aa52 | 1665 | /* Start of Middle stage process */ |
emilmont | 1:fdd22bb7aa52 | 1666 | |
emilmont | 1:fdd22bb7aa52 | 1667 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1668 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1669 | |
emilmont | 1:fdd22bb7aa52 | 1670 | /* Calculation of Middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1671 | for (k = fftLen / 4u; k > 4u; k >>= 2u) |
emilmont | 1:fdd22bb7aa52 | 1672 | { |
emilmont | 1:fdd22bb7aa52 | 1673 | /* Initializations for the middle stage */ |
emilmont | 1:fdd22bb7aa52 | 1674 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1675 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1676 | ic = 0u; |
emilmont | 1:fdd22bb7aa52 | 1677 | |
emilmont | 1:fdd22bb7aa52 | 1678 | for (j = 0u; j <= (n2 - 1u); j++) |
emilmont | 1:fdd22bb7aa52 | 1679 | { |
emilmont | 1:fdd22bb7aa52 | 1680 | /* index calculation for the coefficients */ |
emilmont | 1:fdd22bb7aa52 | 1681 | Co1 = pCoef16[ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1682 | Si1 = pCoef16[(ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1683 | Co2 = pCoef16[2u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1684 | Si2 = pCoef16[2u * ic * 2u + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1685 | Co3 = pCoef16[3u * ic * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1686 | Si3 = pCoef16[(3u * ic * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1687 | |
emilmont | 1:fdd22bb7aa52 | 1688 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1689 | ic = ic + twidCoefModifier; |
emilmont | 1:fdd22bb7aa52 | 1690 | |
emilmont | 1:fdd22bb7aa52 | 1691 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1692 | for (i0 = j; i0 < fftLen; i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1693 | { |
emilmont | 1:fdd22bb7aa52 | 1694 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1695 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1696 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1697 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1698 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1699 | |
emilmont | 1:fdd22bb7aa52 | 1700 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1701 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1702 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1703 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1704 | |
emilmont | 1:fdd22bb7aa52 | 1705 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1706 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1707 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1708 | |
emilmont | 1:fdd22bb7aa52 | 1709 | |
emilmont | 1:fdd22bb7aa52 | 1710 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1711 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1712 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1713 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1714 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1715 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1716 | |
emilmont | 1:fdd22bb7aa52 | 1717 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1718 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1719 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1720 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1721 | |
emilmont | 1:fdd22bb7aa52 | 1722 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1723 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1724 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1725 | |
emilmont | 1:fdd22bb7aa52 | 1726 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1727 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1728 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1729 | |
emilmont | 1:fdd22bb7aa52 | 1730 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1731 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1732 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1733 | pSrc16[i0 * 2u] = ((R0 >> 1u) + (T0 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 1734 | pSrc16[(i0 * 2u) + 1u] = ((R1 >> 1u) + (T1 >> 1u)) >> 1u; |
emilmont | 1:fdd22bb7aa52 | 1735 | |
emilmont | 1:fdd22bb7aa52 | 1736 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1737 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1738 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1739 | |
emilmont | 1:fdd22bb7aa52 | 1740 | /* (ya-yb+yc-yd)* (si2) - (xa-xb+xc-xd)* co2 */ |
emilmont | 1:fdd22bb7aa52 | 1741 | out1 = (short) ((Co2 * R0 - Si2 * R1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 1742 | /* (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1743 | out2 = (short) ((Si2 * R0 + Co2 * R1) >> 16); |
emilmont | 1:fdd22bb7aa52 | 1744 | |
emilmont | 1:fdd22bb7aa52 | 1745 | /* Reading i0+3fftLen/4 */ |
emilmont | 1:fdd22bb7aa52 | 1746 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1747 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1748 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1749 | |
emilmont | 1:fdd22bb7aa52 | 1750 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1751 | /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1752 | /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */ |
emilmont | 1:fdd22bb7aa52 | 1753 | pSrc16[i1 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1754 | pSrc16[(i1 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1755 | |
emilmont | 1:fdd22bb7aa52 | 1756 | /* Butterfly calculations */ |
emilmont | 1:fdd22bb7aa52 | 1757 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1758 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1759 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1760 | |
emilmont | 1:fdd22bb7aa52 | 1761 | /* T0 = yb-yd, T1 = xb-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1762 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1763 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1764 | |
emilmont | 1:fdd22bb7aa52 | 1765 | /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1766 | R0 = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1767 | R1 = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1768 | |
emilmont | 1:fdd22bb7aa52 | 1769 | /* S1 = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1770 | S0 = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1771 | S1 = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1772 | |
emilmont | 1:fdd22bb7aa52 | 1773 | /* Butterfly process for the i0+fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1774 | out1 = (short) ((Co1 * S0 - Si1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1775 | out2 = (short) ((Si1 * S0 + Co1 * S1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1776 | /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1777 | /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */ |
emilmont | 1:fdd22bb7aa52 | 1778 | pSrc16[i2 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1779 | pSrc16[(i2 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1780 | |
emilmont | 1:fdd22bb7aa52 | 1781 | /* Butterfly process for the i0+3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1782 | out1 = (short) ((Co3 * R0 - Si3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1783 | |
emilmont | 1:fdd22bb7aa52 | 1784 | out2 = (short) ((Si3 * R0 + Co3 * R1) >> 16u); |
emilmont | 1:fdd22bb7aa52 | 1785 | /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1786 | /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */ |
emilmont | 1:fdd22bb7aa52 | 1787 | pSrc16[i3 * 2u] = out1; |
emilmont | 1:fdd22bb7aa52 | 1788 | pSrc16[(i3 * 2u) + 1u] = out2; |
emilmont | 1:fdd22bb7aa52 | 1789 | |
emilmont | 1:fdd22bb7aa52 | 1790 | |
emilmont | 1:fdd22bb7aa52 | 1791 | } |
emilmont | 1:fdd22bb7aa52 | 1792 | } |
emilmont | 1:fdd22bb7aa52 | 1793 | /* Twiddle coefficients index modifier */ |
emilmont | 1:fdd22bb7aa52 | 1794 | twidCoefModifier <<= 2u; |
emilmont | 1:fdd22bb7aa52 | 1795 | } |
emilmont | 1:fdd22bb7aa52 | 1796 | /* End of Middle stages process */ |
emilmont | 1:fdd22bb7aa52 | 1797 | |
emilmont | 1:fdd22bb7aa52 | 1798 | |
emilmont | 1:fdd22bb7aa52 | 1799 | /* data is in 10.6(q6) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1800 | /* data is in 8.8(q8) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1801 | /* data is in 6.10(q10) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1802 | /* data is in 4.12(q12) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1803 | |
emilmont | 1:fdd22bb7aa52 | 1804 | /* start of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1805 | |
emilmont | 1:fdd22bb7aa52 | 1806 | |
emilmont | 1:fdd22bb7aa52 | 1807 | /* Initializations for the last stage */ |
emilmont | 1:fdd22bb7aa52 | 1808 | n1 = n2; |
emilmont | 1:fdd22bb7aa52 | 1809 | n2 >>= 2u; |
emilmont | 1:fdd22bb7aa52 | 1810 | |
emilmont | 1:fdd22bb7aa52 | 1811 | /* Butterfly implementation */ |
emilmont | 1:fdd22bb7aa52 | 1812 | for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1) |
emilmont | 1:fdd22bb7aa52 | 1813 | { |
emilmont | 1:fdd22bb7aa52 | 1814 | /* index calculation for the input as, */ |
emilmont | 1:fdd22bb7aa52 | 1815 | /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */ |
emilmont | 1:fdd22bb7aa52 | 1816 | i1 = i0 + n2; |
emilmont | 1:fdd22bb7aa52 | 1817 | i2 = i1 + n2; |
emilmont | 1:fdd22bb7aa52 | 1818 | i3 = i2 + n2; |
emilmont | 1:fdd22bb7aa52 | 1819 | |
emilmont | 1:fdd22bb7aa52 | 1820 | /* Reading i0, i0+fftLen/2 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1821 | /* Read ya (real), xa(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1822 | T0 = pSrc16[i0 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1823 | T1 = pSrc16[(i0 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1824 | /* Read yc (real), xc(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1825 | S0 = pSrc16[i2 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1826 | S1 = pSrc16[(i2 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1827 | |
emilmont | 1:fdd22bb7aa52 | 1828 | /* R0 = (ya + yc), R1 = (xa + xc) */ |
emilmont | 1:fdd22bb7aa52 | 1829 | R0 = __SSAT(T0 + S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1830 | R1 = __SSAT(T1 + S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1831 | /* S0 = (ya - yc), S1 = (xa - xc) */ |
emilmont | 1:fdd22bb7aa52 | 1832 | S0 = __SSAT(T0 - S0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1833 | S1 = __SSAT(T1 - S1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1834 | |
emilmont | 1:fdd22bb7aa52 | 1835 | /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */ |
emilmont | 1:fdd22bb7aa52 | 1836 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1837 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1838 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1839 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1840 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1841 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1842 | |
emilmont | 1:fdd22bb7aa52 | 1843 | /* T0 = (yb + yd), T1 = (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1844 | T0 = __SSAT(T0 + U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1845 | T1 = __SSAT(T1 + U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1846 | |
emilmont | 1:fdd22bb7aa52 | 1847 | /* writing the butterfly processed i0 sample */ |
emilmont | 1:fdd22bb7aa52 | 1848 | /* xa' = xa + xb + xc + xd */ |
emilmont | 1:fdd22bb7aa52 | 1849 | /* ya' = ya + yb + yc + yd */ |
emilmont | 1:fdd22bb7aa52 | 1850 | pSrc16[i0 * 2u] = (R0 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1851 | pSrc16[(i0 * 2u) + 1u] = (R1 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1852 | |
emilmont | 1:fdd22bb7aa52 | 1853 | /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */ |
emilmont | 1:fdd22bb7aa52 | 1854 | R0 = (R0 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1855 | R1 = (R1 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1856 | |
emilmont | 1:fdd22bb7aa52 | 1857 | /* Read yb (real), xb(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1858 | T0 = pSrc16[i1 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1859 | T1 = pSrc16[(i1 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1860 | |
emilmont | 1:fdd22bb7aa52 | 1861 | /* writing the butterfly processed i0 + fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1862 | /* xc' = (xa-xb+xc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1863 | /* yc' = (ya-yb+yc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1864 | pSrc16[i1 * 2u] = R0; |
emilmont | 1:fdd22bb7aa52 | 1865 | pSrc16[(i1 * 2u) + 1u] = R1; |
emilmont | 1:fdd22bb7aa52 | 1866 | |
emilmont | 1:fdd22bb7aa52 | 1867 | /* Read yd (real), xd(imag) input */ |
emilmont | 1:fdd22bb7aa52 | 1868 | U0 = pSrc16[i3 * 2u]; |
emilmont | 1:fdd22bb7aa52 | 1869 | U1 = pSrc16[(i3 * 2u) + 1u]; |
emilmont | 1:fdd22bb7aa52 | 1870 | /* T0 = (yb - yd), T1 = (xb - xd) */ |
emilmont | 1:fdd22bb7aa52 | 1871 | T0 = __SSAT(T0 - U0, 16u); |
emilmont | 1:fdd22bb7aa52 | 1872 | T1 = __SSAT(T1 - U1, 16u); |
emilmont | 1:fdd22bb7aa52 | 1873 | |
emilmont | 1:fdd22bb7aa52 | 1874 | /* writing the butterfly processed i0 + fftLen/2 sample */ |
emilmont | 1:fdd22bb7aa52 | 1875 | /* xb' = (xa-yb-xc+yd) */ |
emilmont | 1:fdd22bb7aa52 | 1876 | /* yb' = (ya+xb-yc-xd) */ |
emilmont | 1:fdd22bb7aa52 | 1877 | pSrc16[i2 * 2u] = (S0 >> 1u) - (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1878 | pSrc16[(i2 * 2u) + 1u] = (S1 >> 1u) + (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1879 | |
emilmont | 1:fdd22bb7aa52 | 1880 | |
emilmont | 1:fdd22bb7aa52 | 1881 | /* writing the butterfly processed i0 + 3fftLen/4 sample */ |
emilmont | 1:fdd22bb7aa52 | 1882 | /* xd' = (xa+yb-xc-yd) */ |
emilmont | 1:fdd22bb7aa52 | 1883 | /* yd' = (ya-xb-yc+xd) */ |
emilmont | 1:fdd22bb7aa52 | 1884 | pSrc16[i3 * 2u] = (S0 >> 1u) + (T1 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1885 | pSrc16[(i3 * 2u) + 1u] = (S1 >> 1u) - (T0 >> 1u); |
emilmont | 1:fdd22bb7aa52 | 1886 | } |
emilmont | 1:fdd22bb7aa52 | 1887 | /* end of last stage process */ |
emilmont | 1:fdd22bb7aa52 | 1888 | |
emilmont | 1:fdd22bb7aa52 | 1889 | /* output is in 11.5(q5) format for the 1024 point */ |
emilmont | 1:fdd22bb7aa52 | 1890 | /* output is in 9.7(q7) format for the 256 point */ |
emilmont | 1:fdd22bb7aa52 | 1891 | /* output is in 7.9(q9) format for the 64 point */ |
emilmont | 1:fdd22bb7aa52 | 1892 | /* output is in 5.11(q11) format for the 16 point */ |
emilmont | 1:fdd22bb7aa52 | 1893 | |
emilmont | 1:fdd22bb7aa52 | 1894 | #endif /* #ifndef ARM_MATH_CM0 */ |
emilmont | 1:fdd22bb7aa52 | 1895 | |
emilmont | 1:fdd22bb7aa52 | 1896 | } |